Note 7 - Investment Securities (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

Schedule of Available-for-sale Securities Reconciliation [Table Text Block]

	September 30, 2021
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	40,206	$	5	$	—	$	40,211
U.S. government agency entities		89,823		1,255		135		90,943
Mortgage-backed securities		798,905		12,490		6,328		805,067
Collateralized mortgage obligations		9,792		—		231		9,561
Corporate debt securities		134,348		514		1,428		133,434
Total	$	1,073,074	$	14,264	$	8,122	$	1,079,216

	December 31, 2020
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	80,948	$	6	$	6	$	80,948
U.S. government agency entities		99,944		441		546		99,839
Mortgage-backed securities		709,709		17,965		606		727,068
Collateralized mortgage obligations		10,358		—		34		10,324
Corporate debt securities		118,271		367		267		118,371
Total	$	1,019,230	$	18,779	$	1,459	$	1,036,550

Investments Classified by Contractual Maturity Date [Table Text Block]

	September 30, 2021
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	45,215	$	45,234
Due after one year through five years		117,088		115,615
Due after five years through ten years		149,474		153,657
Due after ten years		761,297		764,710
Total	$	1,073,074	$	1,079,216

Schedule of Unrealized Loss on Investments [Table Text Block]

	September 30, 2021
	Less than 12 Months				12 Months or Longer				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. government agency entities	$	—	$	—	$	2,403	$	135	$	2,403	$	135
Mortgage-backed securities		399,470		5,632		7,038		696		406,508		6,328
Collateralized mortgage obligations		9,418		219		144		12		9,562		231
Corporate debt securities		91,870		1,144		19,716		284		111,586		1,428
Total	$	500,758	$	6,995	$	29,301	$	1,127	$	530,059	$	8,122

	December 31, 2020
	Less than 12 Months				12 Months or Longer				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	40,952	$	6	$	—	$	—	$	40,952	$	6
U.S. government agency entities		26,390		102		40,009		444		66,399		546
Mortgage-backed securities		1,694		23		8,093		583		9,787		606
Collateralized mortgage obligations		10,131		25		193		9		10,324		34
Corporate debt securities		58,405		267		—		—		58,405		267
Total	$	137,572	$	423	$	48,295	$	1,036	$	185,867	$	1,459